California Air Resources Board California Map with County Boundaries
Ozone Data Summaries (1980-1998)
Shasta County
Year Number of Days Standard Exceeded Ozone Concentrations in ppm
1 hour 8 hour
State
1hr
Federal
1hr
Federal
8hr
Max
1hr
3 Year
4th High*
EPDC*
Max
8hr
3 Year Avg
4th High*
1998 40 3 45 0.14 0.12 0.127 0.126 0.095
1997 8 0 6 0.12 0.11 0.118 0.107 0.086
1996 16 0 14 0.11 0.11 0.114 0.100 0.087
1995 3 0 0 0.10 0.10 0.090 0.084 0.080
1994 7 0 8 0.11 0.11   0.105 0.084
1993 1 0 1 0.11 0.11   0.088 0.083
1992 10 0 10 0.11 0.11 0.117 0.091 0.090
1991 12 0 11 0.11 0.11 0.089 0.095 0.091
1990 13 1 13 0.13 0.11   0.110 0.093
1989 0 0 0 0.09 0.12 0.119 0.083 0.085
1988 5 0 3 0.12 0.12   0.105 0.088
1987 25 2 21 0.13 0.12   0.108 0.091
1986 8 0 9 0.12 0.11   0.097 0.080
1985 10 0 9 0.12 0.10   0.105 0.077
1984 2 0 2 0.10 0.10   0.091 0.082
1983 7 0 4 0.10 0.11   0.093 0.088
1982 5 0 2 0.10 0.11 0.111 0.091 0.091
1981 22 0 20 0.12 0.11 0.116 0.100 0.096
1980 22 0 24 0.11 0.12 0.117 0.097 0.096
* The 3 year 4th high, 3 year average 4th high, and Expected Peak Day Concentration (EPDC) are calculated based on data for 3 successive years, listed by the last year of the three year period.  The EPDC represents the ozone concentration expected to occur once per year.
   

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This page last revised on March 26, 1999

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